不对称偏振控制方案中两束脉冲强度比改变对原子电离及高次谐波产生的影响  

Influence of Intensity Ratio of Two-Beam Pulses on Atomic Ionization and High Harmonic Generation in Non-Symmetric Polarization Control Scheme

作　　者：宋浩 苏宁 陈高[1] Song Hao;Su Ning;Chen Gao(School of Science,Changchun University of Science and Technology,Changchun,Jilin 130022,China)

机构地区：[1]长春理工大学理学院,吉林长春130022

出　　处：《光学学报》2018年第12期280-287,共8页Acta Optica Sinica

基　　金：吉林省基础研究计划(20170101046JC)

摘　　要：偏振控制方案用以产生阿秒脉冲,其高次谐波辐射仅发生在偏振门内的线性半个光学周期,且可得到在整个平台区及截止位置附近皆连续的谐波谱。利用Ammosov-Delone-Krainov隧穿电离理论和强场近似方法,数值模拟了偏振控制方案中两束反向旋转圆偏振脉冲之间强度比对原子的电离几率及高次谐波发射功率谱的影响。研究发现,合理控制两束脉冲的强度比,可确保原子的有效电离发生在偏振门的前1/4光学周期,这有利于得到频域上优化的高次谐波发射谱。此外,可以根据需要在强度比小于1的范围内优化选择谐波谱的截止位置和转换效率。The polarization control scheme is generally used for generating attosecond pulse, in which the high harmonic emission only occurs within a half optical period of polarization gating and thus the obtained harmonic spectrum is continuous in the whole plateau and at the cutoff position. Based on the Ammosov-Delone-Krainov tunneling ionization theory and the strong field approximation method, the effect of the intensity ratio of two-beam counter-rotating circularly polarized pulses in the polarization control scheme on atomic ionization probability and harmonic emission power spectra is investigated by numerical simulation. It is found that if the intensity ratio of two-beam pulses is properly controlled, the effective atomic ionization can take place in the first quarter of an optical period of polarization gating, which is beneficial to obtain an optimal high harmonic spectrum. Moreover, one can optimize the cutoff position and conversion efficiency of harmonic spectra according to the needs, provided the intensity ratio is always less than 1.

关 键 词：原子和分子物理学 高次谐波 偏振控制方案 原子电离 

分 类 号：O437[机械工程—光学工程]